CN110631871B - Sealed piston type supercharged boiler ash taking device and method - Google Patents

Abstract

The invention discloses an ash taking device and method for a sealed piston type supercharged boiler. Inert gas is filled into the pressure container through the charging valve, so that the internal pressure of the ash taking device before working is equal to the pressure of the flue. The invention has the advantages of good sealing performance, high ash taking efficiency and easy maintenance. The ash taking method can solve the problems of flying ash splashing, ash collection amount reduction, environmental pollution caused by flue gas leakage and the like caused by the pressure difference between the inner side and the outer side of an ash taking point, and can avoid the damage to the flue gas flow field structure in the flue in the ash taking process, thereby realizing the safe and efficient ash taking from the high-pressure flue.

Description

A kind of sealed piston type pressurized boiler ash removal device and method

technical field

The invention relates to an ash removal device and method, in particular to an ash removal device and method for a sealed piston type pressurized boiler, belonging to the field of boiler ash removal devices.

Background technique

The basic pattern of coal-based primary energy is difficult to change in the short term, and the clean and efficient utilization of coal is still an important technical issue for energy transformation and development. In thermal power plants, fly ash is an important part of boiler tail flue gas. The results of physical and chemical analysis are of great significance for power plant operation regulation, cost control, design transformation and environmental protection. The supercharged combustion has the advantages of increasing the combustion rate of coal particles, improving the combustion efficiency, and reducing the emission of NO pollutants. Both integrated gasification combined cycle and pressurized oxy-combustion technologies involve a pressurized gasification/combustion process.

Although increasing the reaction pressure has many advantages, the pressurized conditions increase the difficulty of ash extraction, which puts forward higher requirements for the ash extraction device. In the process of ash removal, due to the huge pressure difference between the inside and outside of the ash point, the ash sample often spews out with the high-pressure flue gas, which not only reduces the amount of ash and the efficiency of ash removal, but also causes pollution to the environment. Most of the current ash removal devices are suitable for atmospheric pressure boilers, and are not suitable for ash removal under pressurized conditions. More importantly, these devices will have a huge impact on the internal pressure of the flue during the ash removal process, thereby destroying the flow structure of the flue gas inside the flue. In addition, some ash removal devices are used to deal with continuous ash discharge and a large amount of ash. The system structure is complex, the manufacturing process is difficult and the cost is high, and the collection of ash samples cannot be conveniently and quickly completed in a short time. Work.

SUMMARY OF THE INVENTION

Purpose of the invention: The present invention provides a safe, efficient and environmentally friendly ash removal device and method in a high-pressure flue to solve the above problems.

Technical scheme: The ash removal device of the sealed piston-type pressurized boiler of the present invention includes a pressure vessel, the upper end of the pressure vessel is provided with an inlet pipeline, one side is provided with an inflation valve, the other side is provided with a flue gas outlet pipeline, and the lower end is provided with an inlet pipeline. There is an ash outlet pipeline, and a sealing piston is arranged inside; the sealing piston is moved up and down by adjusting the piston control part to isolate the collected fly ash.

Preferably, the pressure vessel is divided into multiple sections, and each section can be connected by flanges.

When the sealing piston descends to the end, its peripheral side is in sealing contact with the inner wall of the pressure vessel.

The sealing piston is in the shape of a platform, a cone or a truncated cone.

The inlet pipeline is provided with a sampling valve.

The flue gas outlet pipeline is provided with an induced draft fan and a flue gas outlet valve.

The ash outlet pipeline is provided with an ash discharge valve.

The front part of the ash discharge valve is provided with a rotor, and the rotor is connected with the transmission and the motor. Preferably, the rotor can be a star rotor.

A differential pressure gauge is arranged between the flue and the pressure vessel.

An ash removal method for an ash removal device of a sealed piston-type pressurized boiler, comprising the following steps:

a. Close all valves, connect the inlet pipeline of the device to the flue sampling port, and connect the flue gas outlet pipeline to the flue sampling port;

b. Open the inflation valve, and fill the pressure container with inert gas until the pressure in the container is the same as that of the flue;

c. Close the inflation valve, open the valves on the inlet pipe and the flue gas outlet pipe, and the flue gas carrying the fly ash enters the pressure vessel and returns to the flue through the flue gas outlet pipe. At this time, the sealing piston is separated from the wall surface;

d. After the collection is completed, close the valves on the inlet pipe and the flue gas outlet pipe, and move the sealing piston down through the piston control member until it is in close contact with the wall of the pressure vessel;

e. Open the valve on the ash outlet pipeline to discharge the deposited fly ash.

The following steps can also be implemented before the step e:

f. Open the valve on the flue gas outlet pipeline, and discharge the high-pressure flue gas in the space on the upper side of the sealing piston out of the pressure vessel.

g. When the pressure difference between the flue and the pressure vessel is stable, close the valve on the flue gas outlet pipeline and move the sealing piston upward, so that the high-pressure gas on the lower side of the sealing piston enters the upper normal pressure space again. This step is used to release the high pressure flue gas remaining in the lower part of the piston.

When the flue gas outlet pipeline of the ash extraction device is provided with an induced draft fan, the induced draft fan is turned off while performing step b, and the induced induced draft fan is turned on while performing step c.

Beneficial effects: Compared with the prior art, the present invention has the following significant advantages:

(1) The present invention is convenient, fast and reliable to realize the separation of fly ash and flue gas and the work of flue gas pressure relief, and effectively prevent the fly ash from splashing around due to the excessive pressure difference between the inner and outer sides of the ash extraction device of the common ash extraction device. The problem of reducing the amount of ash collected.

(2) The present invention can complete the ash removal process without changing the internal flow structure of the high-pressure flue. At the same time, the extracted flue gas is returned to the flue again, which avoids the problem of environmental pollution caused by flue gas leakage.

(3) The present invention can effectively reduce the residual fly ash in the pressure vessel and improve the collection rate of fly ash by charging and discharging the inert gas during the ash extraction process.

(4) The rotor provided in the present invention can control the discharge rate of fly ash by connecting an external motor and a transmission. At the same time, the rotor itself has good sealing, which can prevent the leakage of fly ash caused by unbalanced pressure difference under unexpected circumstances.

(5) The segmented design of the pressure vessel of the present invention can effectively simplify the disassembly and assembly process, and facilitate the inspection and maintenance of its internal components. Especially when the boiler burns low-quality coal with high ash and high sulfur, a large amount of fly ash is likely to cause certain damage to the internal components of the ash removal device. At this time, the convenient and quick disassembly and assembly design is particularly important.

Description of drawings

Fig. 1 is the structural representation of the present invention;

Figure 2 (a) is a schematic diagram of the separation state of the sealing piston and the container wall of the present invention;

Figure 2 (b) is a schematic diagram of the sealing state of the sealing piston of the present invention and the wall surface of the container;

Figure 3 is a structural diagram of sealing pistons with different shapes.

Detailed ways

The technical solutions of the present invention will be further described below with reference to the accompanying drawings.

As shown in FIG. 1 , an ash removal device for a sealed piston-type booster boiler includes a pressure vessel 2 , an inlet pipe 15 , a flue gas outlet pipe 11 and an ash outlet pipe 11 . The wall of the pressure vessel 2 is provided with an inflation valve 5 and an exhaust valve 6, the other side is provided with a flue gas outlet pipe 11, the top is provided with an inlet pipe 15, the bottom is provided with an ash outlet pipe 16, and a sealing piston is provided inside. 3. The pressure vessel 2 can be divided into multiple sections, and each section is connected by a flange to facilitate the maintenance of the inside of the device. The inlet pipeline is provided with a sampling valve 13 . The flue gas outlet pipeline is provided with an induced draft fan 12 and a flue gas outlet valve 13 . An ash discharge valve 10 is provided on the ash outlet pipeline. A differential pressure gauge 14 is provided between the flue and the pressure vessel 2 .

The sealing piston 3 can be moved up and down by adjusting the piston control member 4 to isolate the collected fly ash. According to the cohesiveness of the ash sample taken, the sealing piston 3 can adopt different shapes, and the sealing piston can be a platform type, a conical shape or a circular frustum type, as shown in FIG. 3 . The platform-type piston has the simplest structure and the lightest weight, but the ash sample is most likely to be deposited on the surface; the conical-type piston has a complex structure, but has the least amount of ash accumulation; the truncated-type piston is in between.

As shown in Figure 2(a), when the sealing piston 3 is separated from the wall of the pressure vessel 3, the lower space of the piston communicates with the upper space, and the ash falls to the lower space in the pressure vessel 2 under the action of gravity. When the sealing piston falls to the end, the pressure vessel is divided into two isolated spaces, and the ash is pressed into the lower part of the pressure vessel 3 and the ash outlet pipeline 11, as shown in Figure 2(b). The outer side of the sealing piston 3 may be provided with a high temperature resistant sealing rubber ring.

The upper part of the ash discharge valve is provided with a rotor 9, which is connected to the transmission 8 and the motor 7, and adjusts its own speed under the action of the transmission 8 and the motor 7 to control the ash discharge rate. The rotor can block the fly ash and protect the fly ash leakage caused by the pressure imbalance inside and outside the ash removal device under special circumstances. The gap between the outer side of the rotor 9 and the wall surface of the pressure vessel is less than 1 mm. The rotor 9 can also be a star-shaped rotor, and the star-shaped rotor has good sealing performance.

Example 1

The ash extraction method of the present invention is described in detail with Embodiment 1, including the following steps:

a. Close all valves (injection valve 1, charging valve 5, exhaust valve 6, ash discharge valve 10 and flue gas outlet valve 13), connect the device inlet pipeline 15 to the flue sampling port A, and connect the flue gas outlet Pipeline 11 to the sample outlet B of the flue.

b. Open the charging valve 5, and fill the pressure vessel 2 with inert gas through the charging valve 5 until the pressure in the pressure vessel 2 is the same as the flue pressure, and the differential pressure gauge 14 shows 0 at this time. The inert gas may also have a certain pressure. The ash removal device has the same pressure as the flue, and will not affect the flow field distribution inside the flue during the ash removal process.

c. Close the inflation valve 5, open the inlet pipe 15, the valves on the flue gas outlet pipe 11 (the injection valve 1, the flue gas outlet valve 13) and the induced draft fan 12, and the flue gas carrying the fly ash enters the pressure vessel 2, and Returning to the flue through the flue gas outlet pipeline 11 , the charging valve 5 , the exhaust valve 6 , and the ash discharge valve 10 are all closed, and the sealing piston 3 is separated from the wall of the pressure vessel 2 .

d. After a certain period of time, when all the inert gases in the pressure vessel 2 and the flue gas outlet pipeline 11 are turned into flue gas, close the valves on the inlet pipeline and the flue gas outlet pipeline 11 (injection valve 1, flue gas outlet valve 13) With the induced draft fan 12, the sealing piston 3 is moved down through the piston control member 4 until it is in close contact with the wall of the pressure vessel. Due to the action of gravity, most of the fly ash is deposited in the space below the sealing piston.

e. Open the flue gas outlet valve 13 and the induced draft fan 12 on the flue gas outlet pipeline 11, and discharge the high-pressure flue gas in the upper space of the sealing piston 3 out of the pressure vessel.

f. When the pressure difference between the flue and the pressure vessel is stable, close the upper flue gas outlet valve 13 and the induced draft fan 12 on the flue gas outlet pipeline 11, and move the sealing piston 3 up to make the high pressure on the lower side of the sealing piston. The gas enters the upper normal pressure space again. Since the volume of the upper space is much larger than that of the lower space, after one or two pressure relief processes, the inside of the pressure vessel can become atmospheric pressure, and the fly ash still remains inside the vessel without carried out by the gas.

g. Open the valve on the ash outlet pipeline 16, and adjust the rotational speed of the rotor 9 through the transmission 8 and the motor 7 to discharge the deposited fly ash. After the ash removal is completed, when there is fly ash remaining in the pressure vessel 2, open the inflation valve 5, the exhaust valve 6 and the ash discharge valve 10 (other valves are closed), and the pressure vessel 2 can be fed through the inflation valve 5. Press inert gas to purge it, and repeat the above process so that the residual fly ash is discharged through the rotor 9 and the ash discharge valve 10 .

Claims (6)

1. a method for retrieving ash based on a sealed piston type pressurized boiler ash removal device, is characterized in that, the described sealed piston type pressurized boiler ash removal device comprises a pressure vessel (2), and the upper end of the pressure vessel (2) is provided with There is an inlet pipeline (15), an inflation valve (5) is arranged on one side, a flue gas outlet pipeline (11) is arranged on the other side, an ash outlet pipeline (16) is arranged at the lower end, and a sealing piston (3) is arranged inside. ); the sealing piston (3) moves up and down by adjusting the piston control member (4); The ash removal method comprises the following steps: a. Close all valves, connect the inlet pipeline of the device to the flue sampling port, and connect the flue gas outlet pipeline to the flue sampling port; b. Open the inflation valve (5), and fill the pressure vessel (2) with inert gas until the pressure in the vessel is the same as that of the flue; c. Close the inflation valve (5), open the valves on the inlet pipe and the flue gas outlet pipe, the flue gas carrying the fly ash enters the pressure vessel, and returns to the flue via the flue gas outlet pipe (11), at this time the piston is sealed (3) Separate from the wall; d. After the collection is completed, close the valves on the inlet pipe and the flue gas outlet pipe, and move the sealing piston (3) down through the piston control member (4) until it is in close contact with the wall of the pressure vessel; e. Open the valve on the ash outlet pipeline to discharge the deposited fly ash; The following steps are implemented before the step e: f. Open the valve on the flue gas outlet pipeline, and discharge the high-pressure flue gas in the space on the upper side of the sealing piston (3) out of the pressure vessel; g. When the pressure difference between the flue and the pressure vessel is stable, close the valve on the flue gas outlet pipeline and move the sealing piston (3) up, so that the high-pressure gas on the lower side of the sealing piston (3) enters the upper normal pressure space again. 2 . The ash removal method according to claim 1 , characterized in that, when the sealing piston ( 3 ) descends to the end, its peripheral side is in sealing contact with the inner wall of the pressure vessel ( 2 ). 3 . 3 . The ash removal method according to claim 1 , wherein the sealing piston ( 3 ) is in the shape of a platform, a cone or a truncated cone. 4 . 4. The ash removal method according to claim 1, characterized in that, an induced draft fan (12) and a flue gas outlet valve (13) are provided on the flue gas outlet pipeline (11). 5. The method for removing ash according to claim 1, wherein the ash outlet pipeline (16) is provided with a rotor (9) and an ash discharge valve (10), and the rotor is connected to the transmission (8) and the motor ( 7). 6. The ash removal method according to claim 1, characterized in that, when an induced draft fan (12) is provided in the flue gas outlet pipeline (11) of the ash removal device, the induced draft fan is closed while implementing step b, and the induced draft fan is turned off while implementing step b. Turn on the induced draft fan at the same time as step c.

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